Open heart surgery using cardiopulmonary bypass (CPB) is one of the most common surgical procedures performed today. Approximately 1,000,000 operations are conducted worldwide each year, of which 500,000 are conducted in the United States alone. Use of CPB can profoundly alter haemostasis as well as injure vital organs, predisposing patients to major haemorrhagic complications and multi organ failure.
Excessive post-operative bleeding necessitating additional surgery occurs in 7% of patients undergoing CPB. Re-operation for bleeding increases hospital mortality, substantially increases post-operative hospital stay and has a sizeable effect on health care costs.
Concerns about transfusion safety, blood product shortages and increasing blood bank costs have generated increased interest in adopting risk-limiting strategies for post-operative bleeding. In order to prevent damage from CBP, several anti-inflammatory agents have been employed during cardiac surgery; and most commonly Aprotinin.
Despite its ability to reduce postoperative bleeding, the use of Aprotinin was abandoned worldwide in 2007 after studies suggesting that its use increased the risk of complications or death. Aprotinin was withdrawn from distribution because studies demonstrated a higher incidence of myocardial infarction in comparison to those treated using other available agents (such as hexacapron). Since the withdrawal of Aprotinin from use, high risk cardiac procedures are prone to high rate of post-operative bleeding. There is thus a continuing need to develop treatments which can be used in conjunction with CPB and effectively reduce post-operative blood loss.